/*
 * Copyright 2025, AutoMQ HK Limited.
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package kafka.log.streamaspect;

import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.storage.internals.log.LogSegment;
import org.apache.kafka.storage.internals.log.LogSegments;

import java.util.Optional;

public class CachedLogSegments extends LogSegments {
    /**
     * Its [[LogSegment.baseOffset]] will always be the largest one among all segments.
     */
    private LogSegment activeSegment = null;

    public CachedLogSegments(TopicPartition topicPartition) {
        super(topicPartition);
    }

    @Override
    public LogSegment add(LogSegment segment) {
        synchronized (this) {
            if (null == activeSegment || segment.baseOffset() >= activeSegment.baseOffset()) {
                activeSegment = segment;
            }
            return super.add(segment);
        }
    }

    @Override
    public void remove(long offset) {
        synchronized (this) {
            if (null != activeSegment && offset == activeSegment.baseOffset()) {
                activeSegment = super.lastSegment().orElse(null);
            }
            super.remove(offset);
        }
    }

    @Override
    public void clear() {
        synchronized (this) {
            activeSegment = null;
            super.clear();
        }
    }

    @Override
    public Optional<LogSegment> lastSegment() {
        synchronized (this) {
            return Optional.of(activeSegment);
        }
    }

    @Override
    public LogSegment activeSegment() {
        synchronized (this) {
            return activeSegment;
        }
    }
}
